In optically active compounds, particularly those used as pharmaceuticals, it is not rare to find that bioactivity, pharmacokinetics, pharmacodynamics, toxicity and the like are different between optical isomers. Therefore, it is required to resolve or separately synthesize optical isomers not only in test and development stages and also in actual production.
An optically active β-hydroxy ester has high versatility as an ingredient for pharmaceuticals or a raw material therefor and, thus, studies on a method for producing it are continued.
A reaction between aldehyde or ketone and a reagent prepared from α-haloester and zinc, a so-called Reformatsky reaction, is extremely useful as a method for producing β-hydroxy esters because of its high versatility. However, such a reaction has not been established as a method for producing optically active compounds. Particularly, high stereoselectivity has not been achieved in a reaction with ketone as described in, for example, J. Chem. Soc., Chem. Commun., 1993, 811; Tetrahedron, 1973, 29, 3659; and Tetrahedron, 1997, 53(10), 3787. In addition, a stereoselective Reformatsky reaction using an asymmetric ligand in a reaction with ketone having a heterocyclic ring has never been studied.
If a Reformatsky reaction were proceeded stereoselectively, an optically active β-hydroxy ester would be obtained. Since a Reformatsky reaction allows coexisting of functional groups such as ester, amide and the like, it will be a high versatile method. Particularly, since there is no practical method for producing optically active tertiary alcohols which are obtained by a reaction with ketone, a high yield and high versatile method for producing them is desired.